Advances in Carbon Dots-Integrated Optical Fiber Sensors

Carbon dots (CDs) have enormous potential in optical sensing applications due to their remarkable physicochemical properties. Benefiting from high specific surface area, rich active sites, bright photoluminescence, high photostability, and biocompatibility, CDs have been widely used as functional layers in optical fiber sensors, resulting in notable improvements in sensitivity, response speed, and environmental stability. This review describes recent advances in CD-integrated optical fiber sensors, with a focus on CD synthesis techniques and their integration with optical fibers for the sensing of diverse analytes, including heavy metal ions, biomarkers, and dyes. CD-integrated fiber sensors exhibit significantly enhanced detection performance in terms of sensitivity, selectivity, repeatability, response time, and recovery time, compared with their CD-free counterparts. Finally, current challenges and future perspectives are discussed. This review aims to provide valuable insights for the design and development of novel CD-integrated optical fiber platforms for sensing chemically and biologically relevant analytes.